[Openstreetmap] qgis isn't so memory hungry
Lars Luthman
larsl at users.sourceforge.net
Wed Mar 2 10:21:48 GMT 2005
Petter Reinholdtsen wrote (2005-12-11, 12:18:58 GMT):
>[Matt Amos]
>> it seems to me that qgis is very memory hungry, even on quite small
>> files.
>
>I believe this is a problem with the GPX import filter, not with qgis
>in general. I tried to convert the GPX files to shapefiles using the
>gpx2shp program available from <URL:http://gpx2shp.sourceforge.jp/>,
>and imported the resulting shapefile info qgis.
>
>I imported track-2004-01.gpx (462639 points) and track-2004-11.gpx
>(133806 points) this way, and the resulting qgis binary is 17 MiB.
>The gpx2shp convert process was >500 MiB at its largest. :)
>
>Thus suggest to me that the GPX import filter in qgis (and the gpx2shp
>convert program) uses a lot of memory, and that qgis is not the memory
>hungry one.
I don't know if any of you still care about this, but this has been
fixed today in the CVS version of QGIS ( http://sf.net/projects/qgis ).
The problem was that we were using Qt's XML parser to parse the GPX
files, and it is appearently crap for parsing large files. The new
code uses expat instead, and I managed to load a 70 MB GPX file in
13 seconds, using at most 50 MB of memory.
This will be in QGIS 0.7, which will be released at some undefined
time in the future (we still have a couple of other issues that
need to be sorted out).
--
Lars Luthman
PGP key: http://www.d.kth.se/~d00-llu/pgp_key.php
Fingerprint: FCA7 C790 19B9 322D EB7A E1B3 4371 4650 04C7 7E2E
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